ISSN: ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology (IJEIT) Volume 7, Issue 6, December 2017

Transcription

1 Pollutant removal uing electro coagulation in meat and poultry proceing watewater Daniel O. Siringi 1, Lilian Mulimi 2, Patrick Home 2, Joeph Chacha 3 Abtract: Thi i a combination of a review paper on the pollutant removal uing electrocoagulation (EC) in meat and poultry proceing watewater. Experiment are conducted on the removal of pollutant from Chicken proceing plant (CPP) watewater uing EC. EC i very efficient for watewater treatment a the pollutant are eaily taken in or exchanged with the anion in the interlayer. Chicken proceing plant (CPP) produce large amount of watewater containing variety of readily biodegradable organic compound, carbohydrate, protein, and fat. The poible re-ue of properly treated CPP watewater would be economic and environment friendly. In thi tudy, we preent our work on treatment of CPP watewater uing EC. Analyi of the EC-treated water for reue in the ame plant i dicued conidering the U.S.EPA regulation. Two type of EC-reactor were ued for thi purpoe. To better undertand the treatment mechanim, EC-floc wa alo characterized uing XRD, SEM-EDS, and FTIR. Index Term Coliform, Electrocoagulation, Pollutant, and Watewater. I. INTRODUCTION Watewater generated during meat and poultry proceing i compoed of a number of pollutant. Thee watewater contitute a variety of readily biodegradable organic. The biodegradable organic are compoed of protein, carbohydrate, and fat. Biodegradable are meaured in term of BOD (Biological Oxygen Demand) and (Chemical Oxygen Demand) [7]. There are a number of conventional parameter that characterize the pollutant in the watewater. The US Clean Water Act (CWA) Section 304(a) (4) define conventional pollutant parameter to include biochemical oxygen demand (BOD), total upended olid (TSS), oil and greae, ph, and fecal coliform bacteria. Thee pollutant are regulated by U.S Environmental Protection Agency [4]. The watewater ha to be treated before it i dicharged into the drainage ytem. EPA, 2009 [1] give Maximum daily effluent limitation for the following regulated parameter in poultry firt proceing: Ammonia (a N), 8.0mg/L; BOD 5, 26mg/L; Fecal Coliform, Maximum of 400MPN; O&G, 14mg/L and TSS, 30mg/L. Effluent limitation for meat and poultry proceor are BOD 5, 2.0g/kg; Fecal Coliform, No limitation; O&G, 1.0g/kg and TSS, 2.4g/kg. Biodegradable organic are removed by aerobic, anaerobic, lagoon, phyical-chemical ytem, and chemical oxidation, advanced oxidation and membrane filtration procee [7]. Aerobic or Anaerobic method are biological procee. Phyico-chemical procee include diolved air flotation (DAF) and coagulation-flocculation (CF) unit. Coagulation (uing metal alt addition: FeCl 3, Fe(SO 4 ) 3, Al 2 (S 4 O) 3 or Ca(OH) 2 ) i a proce of aggregating upended particle to form ettling floc, wherea flocculation (uing cationic, non-ionic or ionic organic polymer) i a proce of agglomerating coagulated-particle into large floc [2]. Thee method have limitation in their operation. Anaerobic treatment procee require high energy conumption for aeration and high ludge. Anaerobic method of poultry laughterhoue watewater i often lowed or impaired due to the accumulation of upended olid and floating fat in the reactor, which lead to a reduction in the methanogenic activity and bioma wah-out. Both biological procee require long hydraulic retention time and large reactor volume, high bioma concentration and controlling of ludge lo, to avoid the wah-out of the ludge [3]. Even though Biological procee are effective and economical, long hydraulic retention time and large area requirement make ometime thee procee le attractive than phyico-chemical treatment, which require horter retention time. Phyico-chemical treatment produce large volume of putrefactive and bulky ludge that require pecial handling and further treatment [2]. Electro-chemical technique uch a, electro flotation (EF), electrode-cantation, electro coagulation (EC), electro kinetic remediation (for contaminated oil) offer the poibility to be eaily ditributed, require minimum amount and number of chemical [6]. Electrochemical procee have lower operating cot compared to the conventional proce, due to the low electric current required [11]. Electrocoagulation (EC) i a promiing technique for treatment of meat and poultry watewater. The EC proce ha attracted a great deal of attention in treating indutrial watewater becaue of it veratility and environmental compatibility. Thi method i characterized by imple equipment, eay operation, a hortened reactive retention period, a reduction or abence of equipment for adding chemical, and decreaed amount of precipitate or ludge which ediment rapidly. The proce ha been hown to be an effective and reliable technology that provide an environmentally compatible method for reducing a large variety of pollutant [3]. The purpoe of thi review i to undertand the effect of proce parameter in the treatment mechanim of Electro coagulation. 16

2 II. MEAT AND POULTRY WASTEWATER CHARACTERISTICS A. Volume of watewater generated Slaughterhoue generate large watewater volume [8]. The ource of watewater in meat proceing i from carca wahing after hide removal from cattle, calve, and heep or hair removal from hog and again after eviceration, for cleaning, and anitizing of equipment and facilitie, and for cooling of mechanical equipment uch a compreor and pump [4]. The mean watewater flow for the operation of producing freh meat i 639 gallon per 1,000 lb LWK [4]. Poultry proceing plant ue relatively high amount of water with an average conumption of 26.5 L/bird during primary and econdary proceing of live bird to meat. Mot poultry proceor ue an average of 26.5 L of water/2.3 kg bird and thi quantity range from 18.9 to 37.8 L/bird baed on the plant facilitie [5]. The typical minimum water uage figure worldwide appear to be m 3 /beat for beef laughtering plant, auming an average live weight 0.5 tonne/beat in the US and Germany [8]. B. Watewater Contituent and Concentration The principal ource of wate in meat proceing are from live animal holding, killing, hide or hair removal, evicerating, carca wahing, trimming, and cleanup operation [3]. Meat proceing wate include blood not collected, vicera, oft tiue removed during trimming and cutting, bone, urine and fece, oil from hide and hoove, and variou cleaning and anitizing compound. The principal contituent of meat proceing watewater are a variety of readily biodegradable organic compound, primarily fat and protein, preent in both particulate and diolved form. Protein and fat which come from carca debri and the blood are the major pollutant in the watewater [5]. The pollutant of concern in meat and poultry proceing watewater are biochemical oxygen demand (BOD), chemical oxygen demand (), total upended olid (TSS), nitrogen, and phophoru. Meat proceing watewater remain high trength wate, even after creening, in comparion to dometic watewater. Blood not collected, olubilized fat, urine, and fece are the primary ource of BOD in meat proceing watewater. Beef cattle blood ha a reported BOD of 156,500 mg/l with an average of 32.5 pound of blood produced per 1,000 pound LWK [4]. The raw Poultry Slaughter Watewater mainly conit of everal organic compound including carbohydrate, tarche, protein, upended particle, and other ingredient. Characteritic of the Poultry Slaughter Watewater are a follow: chemical oxygen demand () 29,000 26,000 mg/l, biochemical oxygen demand (BOD) 12,000 10,000 mg/l, turbidity NTU, oil greae mg/l, total upended olid (TSS) , and initial ph 6.7, conductivity 1.99 ms [3]. 1) Biochemical Oxygen Demand BOD i an etimate of the oxygen-conuming requirement of organic matter decompoition under aerobic condition. When meat and poultry proceing watewater are dicharged to urface water, the microorganim preent in the naturally occurring microbial ecoytem decompoe the organic matter contained in the watewater. The decompoition proce conume oxygen and reduce the amount available for aquatic animal. Severe reduction in diolved oxygen concentration can lead to fih kill [4]. 2) Chemical Oxygen Demand i an etimator of the total organic matter content of both watewater and natural water. It i the meaure, uing a trong oxidizing agent in an acidic medium, of the oxygen equivalent of the oxidizable organic matter preent. i uually higher than BOD becaue include lowly biodegradable and recalcitrant organic compound not degraded microbially during the duration of the BOD tet. i mot ueful; however a a control parameter for watewater treatment plant operation becaue it can be determined in 3 hour a oppoed to the 5 day or more required by BOD (4). 3) Chloride Chloride (Cl-) i a common anion in watewater and natural water. However, exceively high chloride concentration in watewater dicharge can be harmful to animal and plant in non-marine urface water and can dirupt ecoytem tructure. It can alo adverely affect biological watewater treatment procee. Furthermore, exceively high chloride concentration in urface water can impair their ue a ource water for potable water upplie. If odium i the predominant cation preent the water will have an unpleaant tate due to the corroive action of chloride ion [4].Sodium concentration of greater than 1500mg/L in the influent caued poorly ettling ludge and poor effluent quality lab-cale tudie, however, found that ludge could acclimatize to odium level a high a 7000mg/L without deleteriou effect [8]. 4) Oil and Greae In meat and poultry proceing watewater, oil and greae i primarily an etimate of the concentration of animal fat and oil lot during proceing activitie, but it may alo include lubricating oil and greae [4]. Oil and greae in dicharge of meat and poultry proceing watewater i of concern for everal reaon. One i the high BOD of animal fat and oil, which are readily biodegradable, and the impact on the diolved oxygen tatu of receiving water and related impact on aquatic biota. In addition, a film of oil and greae on the urface of receiving water can be unightly and reduce natural re-aeration procee. Soluble and emulified oil and greae can alo inhibit the tranport of oxygen and other gae neceary for plant and animal urvival, alo cauing in aquatic ecoytem diruption. 17

3 5) Indicator Organim The total coliform, fecal coliform, and fecal treptococcu group of bacteria hare the common characteritic of containing pecie that normally are preent in the enteric tract of all warm-blooded animal, including human. Thu, thee group of bacteria are commonly ued a indicator of fecal contamination of natural water and the poible preence of enteric pathogenic bacteria, virue, and paraite of enteric origin. They are ued a indicator of the poible preence of enteric pathogen becaue of their normal preence in generally high denitie in comparion to enteric pathogen, uch a Salmonella and Shigella, and their relative eae of enumeration [4]. 6) Nitrogen The dicharge of high load of nitrogen and phophoru in laughterhoue watewater into enitive water-bodie or onto permeable oill ha emerged a a major problem for the indutry worldwide [8]. Several form of nitrogen are pollutant of concern in meat and poultry proceing watewater. Included are total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH4-N), and nitrite plu nitrate nitrogen (NO2 + NO3-N) [4]. Both ammonia nitrogen and ammonium nitrogen can be directly toxic to fih and other aquatic organim; ammonia (a nitrogen) i the more toxic. In addition, dicharge of ammonia nitrogen can reduce ambient diolved oxygen concentration in receiving urface water becaue of the microbially mediated oxidation of ammonia nitrogen to nitrite plu nitrate nitrogen. Thi demand i known a nitrogenou oxygen demand (NOD). With the depreion of ambient diolved oxygen concentration, population of fih and other aquatic organim are adverely affected, poibly cauing a change in ecoytem compoition and a lo of biodiverity. Ammonia nitrogen in watewater dicharge can alo be reponible for the development of eutrophic condition and the aociated advere impact on ambient diolved oxygen concentration if nitrogen i the nutrient limiting primary productivity. A nitrate, nitrogen i readily mobile in oil and may therefore leach. 7) Solid Meat and poultry proceing watewater before and after treatment contain both upended and diolved olid, which are alo known a nonfilterable and filterable reidue. Thu, upended olid have both organic (volatile) and inorganic fraction. Diolved olid conit primarily of diolved inorganic compound (mainly calcium, magneium, iron, manganee, and ulfur compound), but they can alo contain colloidal organic material. The principal ource of diolved olid in meat and poultry proceing watewater are potable water upplie ued for proceing; alt ued in proceing, uch a odium chloride; and cleaning and anitizing agent. Uually, the organic, and therefore potentially biodegradable, fraction of upended olid i ubtantially higher than the inorganic fraction; the revere i typically characteritic of diolved olid. Total olid are the um of upended and diolved olid with total volatile olid, or total volatile reidue repreenting an etimate of the organic fraction of total olid. Supended olid that ettle to form bottom depoit can create anaerobic condition becaue of the oxygen demand exerted by microbial decompoition. They can alter habitat for fih, hellfih, and benthic organim. Supended olid alo provide a medium for the tranport of other orbed pollutant, including nutrient, pathogen, metal, and toxic organic compound uch a peticide, which accumulate and are tored in ettled depoit. III. PARAMETERS AFFECTING POLLUTANTS REMOVAL EFFICIENCIES A. Effect of current denity The commonly ued electrode are Aluminum and Iron. removal efficiency i higher for aluminum than for Iron electrode. Above current denity of 150Am -2, removal efficiency reache a limit value of 92% for aluminum, and 85% for Iron [3]. Ue of Iron electrode ha higher efficiency for removing oil greae compared to Aluminum electrode. Higher efficiencie are obtained; 94% with aluminum and 99% with Iron [3]. Uing mild teel or aluminum electrode, removal efficiency wa maximal at the 0.3A current intenity. B. Effect of time The decreaed rapidly over the firt 20min of the treatment and then remained quite table until the end of experiment, uing either aluminum or mild teel electrode [2]. The maximal decreae of decreaed lightly between 20 and 60 min and remained quite table until the end of the experiment. C. Effect of upporting electrode Exce Electrode impoe energy demand on the ytem without any ignificant effect on the performance ( removal efficiency). D. Effect of ph High removal percent may be attained in acidic medium, the efficiency decreaing with increaing ph; at ph 2, maximum removal attainable i 93% with aluminum electrode, and 85% with iron electrode. Meanwhile, when original PSW (ph 6.7) i treated by EC, removal i 70% for aluminum, and 60% for iron electrode [3]. IV. EXPERIMENTAL Chicken watewater of 2000 ml wa ued in Kaelco and Plexigla continuou flow reactor. Five iron electrode were ued in each of the reactor. The electrode were properly crubbed and rined prior to each experiment to make their urface clean and free from paive oxide layer. Thee electrode were in the hape of a rectangular. The urface area of each electrode wa 600 cm 2. In the Kaelco reactor [9], the electrode are horizontally arranged, and one end i connected to anode and another end i connected to cathode. A peritaltic pump i ued to flow the 18

4 water through the reactor of 500 ml volume. On the other hand, in the Plexigla reactor, the electrode are vertically arranged. The volume of the Plexigla reactor i 1250 ml. A ph meter calibrated at 7-10 ph range wa ued to meaure ph of watewater before and after treatment. Conductivity meter wa ued to meaure the conductivity in ms. Hach Reactor DRB 200 wa ued to diget the vial. Hach DR 3000 pectrophotometer wa ued for colorimetric meaurement of Vial. Kaelco Power rectifier wa ued to upply current. SEM-EDS, XRD and FTIR were ued to check the compoition of the floc EC Procedure: The electro coagulation unit wa connected to Kaelco power electrifier with the anode connected to the poitive terminal and cathode to the negative terminal. A volume of 2 liter of chicken plant proce watewater wa ued for thee experiment. Two type of flow reactor were ued namely; KASELCO unit and PLEXI-GLAS. A flow rate of 0.5 L per minute wa applied. Effect of current and time were determined. Current wa varied from 0.5A to 3A (0.5A, 1.0A, 2A, 3A). The current and voltage during the EC proce were checked uing Cen-Tech multimeter. For each current 4 ample were collected at an interval of 4 minute. The ample were then teted for. The conductivity wa increaed by NaCl upport electrolyte. The ph of the olution wa meaured during the EC by Oakton ph meter. The floc formation wa oberved. After EC, the final olution wa filtered by funnel and filter paper. The filtrate wa collected in clean flak container for the etimation. The olid reidue EC-floc wa dried ufficiently and characterized uing SEM-EDS, and FTIR. Etimation: When uing 0-15,000mg/L vial a 0.2ml of the filtrate obtained in EC wa added to the Hach vial uing a volumetric pipette. When uing 0-1,500mg/L vial 2ml of filtrate wa added. The Hach Reactor DRB 200 wa ued in digeting the ample. reult were determined calorimetrically. Hach DR 3000 pectrophotometer wa ued for colorimetric determination. V. RESULTS AND DISCUSSION EC experiment were performed on CPP watewater at different current denity and reidence time uing vertical and horizontal EC reactor. Removal Efficiency (RE) and Electrical Energy Conumption (EEC) per volume of watewater were calculated uing equation 1 and 2 [6]: C0 C RE % 100 (1) C0 where, C 0 and C are the concentration of before and after EC, repectively, ppm. VIt v EEC (2) Where, EEC i the electrical energy conumption (kwhm -3 ), V i the potential (V), I i the current (A), t i the time (h), and v i the volume of olution (m 3 ). Current denity wa changed from 0.4 ma/cm 2 to 2.5 ma/cm 2 at different reidence time and it wa found that at current denity 2.5 ma/cm 2 the removal efficiency i the highet for both vertical and horizontal reactor. Figure 1 and 2 how the removal at different reidence time uing vertical and horizontal reactor, repectively. With the ue of vertical EC unit, removal efficiency wa found of 95% at 8 min reidence time, wherea, with horizontal EC unit, it wa 68.9% at 16 min reidence time. Thi reult indicate the better removal efficiency with vertical electrode aembly in the vertical unit than the horizontal aembly in the horizontal unit. It ha been already theoretically determined that the maximum current denity occur at the edge or tip of the electrode [10]. Since in the horizontal aembly edge of the electrode are encloed in the frame and not expoed to the electrolyte olution, the removal efficiency i lower for thi type of aembly. On the other hand, in the vertical electrode aembly, three edge of the electrode are expoed to the electrolyte olution and are more uceptible for producing more GR and thu better treatment of the pollutant preent in CPP water. Figure 3 how the ph change againt reidence time uing vertical unit. It how that during EC, the ph increae from 7.0 and tabilize at about 7.6. In cae of horizontal unit, during EC the ph alo increae from 7.0 and tabilize a bit higher ph value, i.e., 8.4 a hown in Figure 4. The higher reidual hydroxide concentration in the horizontal unit probably ignifie the le conumption of thee ion for GR formation and removal. GR ha inherently hydroxide ion in it tructure. removal in EC may alo require the conumption of hydroxide ion. Table I how reult of thoe experiment performed at optimal operating condition providing highet removal efficiencie. The current denity 2.5 ma/cm 2 indicate the current intenity of 3 A. Table I alo how the calculation of EEC per volume of watewater for the horizontal reactor and the vertical reactor. It wa found that EEC per volume for vertical unit at highet removal efficiency i lower (3.4 kwh/m 3 ) than that for horizontal unit (3.8 kwh/m 3 ). That mean, le electrical energy wa conumed in the vertical EC unit than in the horizontal EC unit. The reaon for thi fact may be the deign of the reactor. Material Characterization: The SEM micrograph of EC treated CPP watewater floc how the preence of carbon, oxygen, aluminum, ilicon, potaium, odium, chlorine, calcium and iron element (Figure. 5). Carbon, oxgyen and iron repreent 34.73%, 17.49% and 43.39% by weight in the floc, repectively. The preence of carbon and oxygen indicate that CPP watewater contain organic compound. The preence of iron with highet percentage indicate the iron hydroxide that 19

5 i produced a green rut. Figure 6 how the XRD diffraction pattern of the EC-floc. The XRD pattern indicate the preence of magnetite (Fe 3 O 4 ), goethite (FeO(OH)), and wuetite (FeO). The green colored and the pale-red colored pattern are for the EC-floc produced by the horizontal reactor and by the vertical reactor, repectively. The equivalent abolute value for the removal efficiency of 95% with the vertical reactor i 180 mg/l. U.S. EPA doe not mention any threhold value or limit for drinking water criteria or effluent dicharge from CPP. We need further tudie on BOD, TSS, ammonia and other parameter for coming to the concluion for re-ue of EC-treated CPP watewater. Thee invetigation are in progre. VI. CONCLUSION Electro coagulation technique remove mot of the pollutant in meat and poultry wate water. The removal of the pollutant achieve the et effluent limitation by EPA. Mot of the reult how aluminum electrode are more efficient compared to iron electrode. However, from the literature review no work ha been done to evaluate the removal of (Ammonia a N), Chloride, Phophoru and Total coliform uing Electrocoagulation. Alo not much work ha been done to evaluate the removal of TSS and BOD 5 in meat and poultry proceing watewater. The effect of flow rate on the removal ha alo not been evaluated. There more invetigation need to be done to determine the removal efficiency of TSS, BOD 5, coliform, Chloride, Ammonia (a Nitrogen) and phophoru. The effect of flow rate need to be determined. The EC proce uing vertical and horizontal reactor demontrate that green rut, the layered double hydroxide coniting of Fe(II)-Fe(III) ion are effective in treating pollutant in chicken proceing plant watewater. The maximum removal wa achieved with the current denity of 2.5 ma/cm 2 when EC wa performed with Fe-Fe electrode. With vertical EC reactor, 95 % removal efficiency wa attained with a reidence time of 8 minute, wherea, with horizontal EC reactor, 68.9 % removal efficiency wa realized with a reidence time of 16 minute. The higher removal efficiency with vertical EC reactor may be jutified for the occurrence of highet current denity at the expoed edge of the vertical electrode and thu forming larger amount of GR, while for the horizontal EC reactor, the edge of the electrode are encloed to the frame of EC reactor. The electrical energy conumption per volume of watewater wa calculated and obtained a 3.8 and 3.4 kwhm -3 for the horizontal and vertical reactor, repectively, for highet removal. No report of phophoru removal from a laughterhoue watewater have been publihed. Fig 1. removal with reidence time uing vertical EC unit reactor at 2.5 ma/cm 2 current denity Fig 2. removal with reidence time uing horizontal EC unit Reactor at 2.5 ma/cm 2 current denity Fig 3. PH change with reidence time in the vertical unit reactor at 2.5 ma/cm2 current denity. Fig 4. PH change with reidence time in horizontal EC unit reactor at 2.5 ma/cm2 current denity 20

6 Table I: The table below how the removal efficiencie with 2 different kind of Reactor. Table 4: Current 2A, 2g/L Nacl Support electrolyte: Initial -470 ppm, Final -139ppm Table 2: Current 1A, 1g/L Nacl Support electrolyte: Intial -470 ppm, Final -126ppm Table 5: Current 3A, 4g/L Nacl Support electrolyte: Intial -470 ppm, Final -150ppm Table 3: Current 1.5A, 1g/L Nacl Support electrolyte: Initial -470 ppm, Final -140ppm Fig 2. SEM micrograph of EC treated Chicken plant proce watewater floc 21

7 Fig 3. XRD pattern of the chicken plant proce EC treated floc. The red line pattern pecifie magnetite ACKNOWLEDGEMENT We greatly acknowledge the financial upport from the National Council of Science and Technology to have made it poible for thi work to be carried out. Further we wih to thank Jomo Kenyatta Univerity for allowing u to ue their laboratory and taff for being very co-operative more epecially at the initial tage of fabrication of the Electrocoagulation ytem. We alo acknowledge the Univerity of Eldoret adminitration to have provided a conducive environmental for the Primary reearcher in thi work Dr. Siringi Daniel to carry out thi work and allow him everal time to travel to the laboratorie in Jomo Kenyatta Univerity of Agriculture and Technology. We finally appreciate the contribution of Mr. Ngigi of the National Council of Science and Technology REFERENCES [1] US EPA, Title 40: Protection of Environment: Part 432- Meat and poultry product point ource Category, e-cfr Data, [2] Mélanie Aelin, Patrick Drogui, Hamel Benmoua, Jean-Franҫoi Blai. Effectivene of electrocoagulation proce in removing organic compound from laughterhoue watewater uing monopolar and bipolar electrolytic cell, Chemophere 72 (2008) [3] Mehmet Kobya, Elif Senturk, Mahmut Bayramoglu, Treatment of poultry laughterhoue watewater by electrocoagulation, Journal of Hazardou Material B133 (2006) [4] US EPA, Technical Development Document for the Final Effluent Limitation Guideline and Standard for the Meat and Poultry Product Point Source Category (40 CFR 432): EPA-821-R [5] Rameh Y. Avula, Heather M. Nelon, Rakeh K. Singh. Recycling of poultry proce watewater by ultra filtration, Innovative Food Science and Emerging Technologie [6] Mohammad Y.A. Mollah, Paul Morkovky, Jewel A.G. Gome, Mehmet Kehmet Kemez, Joe Parga, David L. Cocke. Fundamental, preent and future perpective of electrocoagulation, Journal of Hazardou Material B114 (2006) [7] Metcalf & Eddy Inc., George Tchobanoglou, Franklin L Burton, and H.David Stenel, Watewater Engineering: Treatment and Reue (McGraw Hill Higher Education, New York, 2003), Page 32. [8] M.R. John, Development in Watewater. Treatment in the Meat Proceing Indutry: A Review, Bioreource Technology, 54 (1995) [9] Hector A. Moreno-Cailla, David L. Cocke, Jewel A.G. Gome, Paul Morkovky, J.R. Parga, Eric Peteron, Electrocoagulation mechanim for removal, Separation and Purification Technology, 56(2) (2007) [10] Greenberg A.E., Cleceri L.S., Eaton A.D., APHA-AWWA and WEF, STANDARDS for Examination of water and watewater, 21t edition, [11] Pablo Caňizare, Carlo Jiménez, Fabiola Martínez, Manuel A. Rodrigo, Critina Sáez. The ph a a key parameter in the choice between coagulation and electrocoagulation for the treatment of watewater, Journal of Hazardou Material [12] Ümran Tezcan Ün, A. Savaş Koparal, Ülker Bakir Öğütveren. Hybrid procee for the treatment of cattle-laughterhoue watewater uing aluminum and iron electrode, Journal of Hazardou Material [13] G. Mouedhen, M. Feki, M. De Petri Wery, H.F. Ayedi. Behavior of aluminum electrode in electrocoagulation proce, Journal of Hazardou Material 150 (2008)

8 Referenc e pollutant ph Current or current denity or Electrical Energy Conumption (EEC) 20mA/cm 2 Cell voltag e (v) Supporting Electrode Concentratio n 0.05M Na 2SO 4 Electrode material electrode Connection Operatin g time (min) Removal path Flo w rate Treatment efficiency (%) Reactor mA/cm 2-547kwh/m 3-158kwh/m Al Batch 0.05M Na 2SO 4 Fe Batch - 25mA/cm 2, 399kwh/m 3 Al Batch - 10mA/cm 2, 138kwh/m 3 Al Batch - 15mA/cm 2, 83kwh/m 3 Fe Batch - 25mA/cm 2, 124kwh/m 3 Fe Batch 0.05M Na 2SO 4 Al Batch 0.1M Na 2SO 4 Al Batch A, Na 2SO kwh/m 3 Fe Bipolar A, Na 2SO kwh/m 3 Al Bipolar A, Na 2SO kwh/m 3 Oil-greae Oil-greae Oil-greae Oil-greae Oil-greae Oil-greae A, kwh/m kwh/m 3, 150/m kwh/m 3, 150/m kwh/m 3, 150/m kwh/m A/m A/m kwh/m kwh/m kwh/m 3 Na 2SO4 Fe Monopolar Monopolar Al Al Fe Al Fe Fe Fe Al Al Al Fe Bipolar 23

9 Oil-greae Oil-greae Oil-greae kwh/m 3 Fe A/m 2 Al A/m 2 Fe kwh/m3 0.1M NaSO4-547kwh/m3 0.05M NaSO Al Al Al Fe Fe Batch Batch Batch Batch Bipolar BOD Fe Bipolar TSS Fe Bipolar 24